The present invention relates to method for controlling a reaction force applied on an accelerator pedal of a motor vehicle in order to improve eco-driving.
Typically, an accelerator pedal system is provided in a motor vehicle, and an accelerator pedal is depressed by driver's foot in order to increase a vehicle speed.
According to a conventional accelerator pedal system, the accelerator pedal is connected to a throttle valve via an electric circuit and via at least one electric actuator to modify the degree of opening of the throttle valve depending on a position change of the accelerator pedal.
Motor vehicles are commonly provided with speed limiter wherein a target speed of the vehicle speed can be adjusted by the driver. In this case an added reaction force is applied on the accelerator pedal, typically by an electric motor, at a threshold depression angle of the accelerator pedal that is determined depending on the target vehicle speed. The added reaction force is generally activated on the accelerator pedal when the speed of the vehicle approaches the target vehicle speed in order to limit or reduce the acceleration rate of the vehicle engine each time the depression angle of the accelerator pedal reaches the threshold depression angle so that the vehicle can't exceed the target speed.
Such a common speed limiter doesn't encourage a driver to perform eco-driving in order to reduce fuel consumption of the vehicle because as long as the current speed of the vehicle is far below the target speed, the driver has the possibility to control acceleration of the vehicle and its engine, at a high rate without triggering the added reaction force.
It therefore appears that there is room for improvement to control a reaction force applied on an accelerator pedal of a motor vehicle in order to improve eco-driving and so to reduce fuel consumption of a motor vehicle.
It is desirable to provide an improved motor vehicle which can overcome the drawbacks encountered in traditional motor vehicles, from the eco-driving perspective.
The invention relates, according to an aspect thereof, to a method for controlling the acceleration of a motor vehicle from a cumin vehicle speed. Wherein said motor vehicle comprises an accelerator pedal system able to generate on the accelerator pedal an added reaction force when the depression of the accelerator pedal reaches or is about to reach a given depression level.
Said method comprises the steps of:
a) measuring the current vehicle speed;
b) determining a target speed of the motor vehicle depending at least on the current vehicle speed or determining from the current vehicle speed a maximum acceleration rate;
c) determining at least one threshold depression level of the accelerator pedal that corresponds to the stabilization of the vehicle speed at the target speed or that corresponds to the maximum acceleration rate;
d) generating an added reaction force on the accelerator pedal if the depression of the accelerator pedal reaches or is about to reach the threshold depression level;
wherein at least steps a), b) and c) are automatically repeated as the vehicle speed increases.
The method allows a limitation of the acceleration rate of the vehicle during acceleration phases. Number of acceleration peaks during acceleration phases and intensity level of these acceleration peaks can also be reduced.
Thanks to this control the fuel consumption of the vehicle can be greatly limited during accelerations phases of the vehicle.